An apparatus of the above kind is known, e.g. from JP S52-4170 Y2. It serves for, e.g., attaching a snap button to a garment. To this end, the prong ring is placed on the first redirecting member, which redirecting member is a pin with a circular cross section and a diameter slightly smaller than the ring of the prong ring so that prongs which are bent inwardly are redirected by positioning the prong ring on the pin and moving it relative to the pin in the axial direction thereof. If the prongs of the prong ring are not straight, i.e. if they do not extend in the direction in which the lower and upper dies approach one another, there is a chance that the prongs do not penetrate the substrate, but are (further) bent and remain on the first side of the substrate instead of being pushed therethrough. This results in a malfunction of the attaching apparatus.
A similar apparatus is known from WO 2012/131879 A1.
WO 2014/049881 A1 discloses an inspection device for inspecting whether or not prongs of prong rings are suitably directed.
In the case of JP S52-4170 Y2 it is difficult to position the prong ring on the pin, particularly if the prongs are bent inwardly. This applies not only if the prong rings are manually positioned on the pin, but also if they are positioned automatically by the attaching apparatus.